Hydraulic braking system for motor vehicles



Sept. 8, 1936. E. c. HE SS ET AL 2,053,557

HYDRAULIC BRAKING SYSTEM FOR MOTOR VEHICLES s sheets-sheet 1 Filed Aug. 20, 1954 Edward [If-Hess E23 Hass- Wfi Q/W/Z Sept. 8, 1936. E. c. HESS ET AL I HYDRAULIC BRAKING' SYSTEM FOR MOTOR VEHICLES Filed Aug. 20, 19:54 a She'ets-Sheet 2 I? a 4 Q .92

Edward E Hess Emll 255 l I Sept. 8, 1936. E. c. HESS ET AL HYDRAULIC BRAKING SYSTEM FOR MOTOR VEHICLES Filed Aug. 20, 1954 v3 Sheets-Sheet 3 8 a 0 m m h 7 a 6 M w p z .40. l w I x W a 4 ((M r s n W 6 n w E E m Edward E-Hess' 52 Patented Sept. 8, 1936 UNITED'STATES PATENT OFFICE assess:

nvnnsnuc nnaxmc sis-ram ron moron. vsmcnes Edwardflliessandlmilfleslinerlimwia, assignorsofone-thirdtolLPanLBerlin,

' Application August $0, 1934, Serial No. 740,888

6 clim- (cl. sea-a4) This invention appertains to motor vehicles, and more particularly to hydraulic braking systems therefor. Hydraulic brakes are considered by many 5 manufacturers to be the best equipment for motor vehicles. However, this type of brake has certain inherent characteristics which render the brakes objectionable. Thus, should a leak occur between the master cylinder and any one oi. the four wheel-brakes, substantially the entire system is drained of its oil or other operating fluid. Not only does this result in an undue waste of fluid, but the entire braking system is rendered imperative. .This usually occurs without the knowledge of the vehicle operator. Hence, many bad accidents occur from this cause.

It is, therefore, the prime object of our invention to provide a hydraulic braking system, so constructed that should. a leak occur either in the line leading to the two front brakes or the two rear brakes, or in the wheel brakes themselves, such front or rear brakes only will be rendered inoperative (with a loss of fluid) leaving two operative brakes on the front or rear wheels, as the case may be, for perfect control of the vehicle.

Another salient object of my invention is the provision of means for automatically signalling the operator of the vehicle and indicating whether the front or rear brakes are inoperative, should a leak occur, thereby goving the operator notice that repairs to the brakes should be made.

We are familiar with the fact that it has been proposed to utilize floating valves in the line (see the patent to Edward C. Hess, No. 2,008,393, issued July 16, 1935) ,i'or cutting oi! loss of fluid to a leaky wheel brake. However, such devices are diflicult and expensive to install and somewhat diflicult to manipulate after a leak occurs.

40 Therefore, a further salient object of our invention is to provide an especially simple, compact, and durable-structure which can be connected to or from a direct part of the mastercylinder for efliciently cutting off the front or rear brakes, should a leak occur in either of the front or rear brakes, and for signalling to the operator of such leak, together with novel means for controlling the flow of 'fluid to the opposite sides of the floating piston valves from the master cylinder. A further object of our invention is the provision of a safety device for hydraulic brakes embodying a pair of parallel cylinders cast en blockfor direct ionnection with'the cylin- 65 der for receiving the floating piston valves, one

cylinder and piston valve being utilized for th front brakes, and the other cylinder and piston valve for the rear brakes, with a single control valve for directing the flow of fluid to one side of the floating piston valves during normal op- 5 eration of the brake and for controlling the flow of fluid to the other side of the piston valves to facilitate the recharging of the system after the occurrence of a leak and the repair of such leak. 10

A further object of our invention is the provision of novel means for constructing the single valve, whereby the bleeding of the cylinders is permitted in rear 0! the floating piston valves during the recharging of the system to permit the 15 piston valves to return to their normal operative A further object of our invention is to provide a safety device for hydraulic brakes which can either be attached to a conventional master 20 cylinder of a hydraulic brake system or cast as a part of the master cylinder and reservoir for new car installations, novel means being provided for taking care of the expansion oi the fluid during thesummer season. 5

A further object of our invention is the provision of novel means arranged the reservoir of the system for effectively preventing the splashing oi. oil in the reservoir incident to the travel of the vehicle over a roadway, whereby the emul- 30 sifying of the oil will be prevented.

A further object of our invention is the provision of novel means for constructing the floating piston valves to facilitate sliding movement thereof in their cylinders without leakage of the fluid 35 past the valves, and for closing a circuit through a signalling device .when the same reach their extreme forward position, should loss of fluid ocour in the line.

A further object of our invention is the provi- 40 sion of means for closing a circuit through the rear stop signal upon the operation of the master piston for applying the brakes.

A still further object of our invention is the provision of novel means for forming a lubricating 45 hearing for the master cylinder piston rod, and for preventing the entrance of dust-and road grit in the master cylinder.

with these and other objects fin view, the invention consists in the novel-construction, arrange!- 50 ment, and formation of'parts, as will be hereinafter more specifically described, claimed, and illustrated in the accompanying drawings in which drawings: a

Figure 1 is a fragmentary top plan view illustrating our improved safety device incorporated directly with the master cylinder and reservoir of a hydraulic brake;

Figure 2 is a detail vertical section taken sub stantially on the line 22 of Figure 1, looking in the direction of the arrows, illustrating the means employed for permitting the escape of fluid from the safety cylinders upon expansion of the fluid in the cylinders;

Figure 3 is a. longitudinal section through one of the safety cylinders taken substantially on the line 3-3 of Figure l, lookingin the direction of the arrows;

Figure 4 is a vertical longitudinal section through the improved safety device incorporated with .the master cylinder and reservoir of a hydraulic brake, the view being taken substantially on the line 44 of Figure 1; a

Figure 5 is a horizontal sectional view taken substantially on the line 5-5 of Figure 4;

Figure 6 is a detail vertical sectional view through the single control valve;'

Figure 7 is a diagrammatic view showing a vehicle chassis in plan with our improved device incorporated therewith;

Figure 8 is a rear elevation showing my improved safety device made as an attachment for hydraulic braking systems already installed on motor vehicles in use, the device being shown removed from the master cylinder;

Figure 9 is a transverse section through the improved safety device, taken substantially on the line 9-4 of Figure 8, showing the same applied to a fragment of a master cylinder.

Referring to the drawings in detail, wherein similar reference characters designate corresponding parts throughout the several views, the letter A generally indicates our improved safety device. This safety device, as shown in Figures 1 to 5, inclusive, can be cast as a part of the. master cylinder land reservoir of'the hydraulic braking system. The reservoir I is preferably formed on top of the master cylinder l0, and can be provided with a removable cover I2. This cover is firmly held in place by the use of cap screws l3, and a gasket l4 can be interposed betweenthe cover and the reservoir. In order to prevent the splashing of the fluid in the reservoir, we provide an anti-splash device i5. This-antisplash device [5 includes spaced horizontal plates l5 and spaced vertical plates II. ese plates extend, respectively, the length, width, and height of the reservoir, and can be provided with openings l8 to facilitate the draining of the fluid therethrough. r

- Reciprocally mounted within the master cylinder |0 is an operating piston l3. This piston I! can include a metallic body portion 20 having outwardly extending stems 2| around which are fitted rubber gaskets or the like 22. Connected to the rearmost stem 2| ,of the piston is a coupling head 23-to which is attached-the operating rod 24. This operating rod 24 is actuated through the use of any suitable mechanism from a foot pedal formed on a dome-shaped head plate 25. This head plate is flrmly secured in place by the use ofscrews 21 to flanges on the reservoir and'the cylinder. A leather or like diaphragm 23 is carried by the coupling 23 and has its edges clamped between the head 26 and the flanges of the reserv olr and cylinder. This diaphragm effectively prevents the entrance of dust and dirt into the mastercylinder and also creates an air suction.

-An expansion coil spring 29 can be interposed The rod 24 extends through .a bearing 25' between the cylinder l0 and the coupling'23, for normally urging the piston to the rear end of the cylinder. A packing gland 30 is carried by the bearing 25, and an oil cup 3| can be provided for lubricating the packing to facilitate the movement of the rod through the gland.

Our improved safety device A comprises a block 32 having a pair of like spaced parallel cylinders 33 and 34 formed therein. This block 32 is cast on the forward end of the cylinder l0 and the reservoir II, and the cylinders 33 and 34 extend transversely of the master cylinder. The block 32 has formed therein a transversely extending passageway 35 disposed below the cylinders 33 and 34, and this passageway communicates with the forward end of the master cylinder H). A longitudinally extending passageway 35 is formed in the block 32 between the cylinders 33 and 34, and one end of the longitudinal passageway 36 communicates with'a transversely extending passageway 31 formed adjacent to the rear ends of the cylinders 33 and 34. Ports 38 and 39 connect the transversely extending passageway 31 with the rear ends of the cylinders 33 and 34.

The forward ends of the cylinders are opemand are normally closed by removable screw threaded bore 42 communicates with the main transverse- 1y extending passageway 35. Slidably mounted within the cylinders 33 and 34 are novel floating piston valves 45 and 45. These piston valves are constructed similar to the main operating piston 22, only on a smaller scale, and hence each of the piston valves include a metallic body 41 having oppositely extending stems 48 over which are sprung the novel rubber gaskets 49. These rubber gaskets are slightly oversize, so as to insure proper contact thereof with the cylinder walls.

It will be noted that the outer faces of the rubber gaskets are provided with annular grooves which facilitate the expansion and contraction of the gaskets. The outer faces of the metallic 'bodies 41 of the floating pistons are provided with annular grooves in which is fltted a special packing 50, for engagement with the cylinder walls. This construction of floating piston valves allows reciprocatory movement thereof, but efllciently prevents the leakage of fluid around the same.

Received within the tapered bore or valve seat 42 is the single control valve 5|. This valve 5| is of the plug type, and includes an outwardly extending stem 52 to which can be secured a manipulating handle 53. Movement of the handle 53 is limited by a stop lug 54 cast on one of the cylinders. A nut 55 securely holds the valve 5| on its seat. This valve 5| is provided with a vertical bore 56 having communicating therewith diverging passageways 51 and 58, and a main passageway or port 59, which is adapted to normally align with the longitudinal passageway 35.

A diagonally'extending bleed passageway 60 metrically opposite the, diverging passageways 51 and 58. The forward ends of the cylinders 33 and 34 have formed thereon bosses GI and 62, and .7

these-bosses communicate respectively with the forward ends of the cylinders 88 and 3|, and have nected by means of a wire 8! to one terminal of the conductor rods a and n, and establish an connected therewith fluid conductor tubing 83 and 64, which lead respectively to the front and rear pairs of brakes.

By referring toFigure'l itcanbeseenthatthe tubing 63 terminates in a T 85, to which is connected the branch pipes or tubes 88, which lead to the brakes for the front wheels. The tube 8| terminates in a T l which has communicating therewith pipes I! which lead to the brakes for the rear wheels.

Extending through the heads 48 and II of the cylinders 83 and 34 are contact rods 8 and II. These contact rods are insulated from the beads by means of non-conductor sleeves II which surround the rods. Binding nuts I! are threaded on the rods to permit the connection of electrical conductors I3 and II therewith. The binding nuts 12 are insulated from the heads 48 and II by washers 15 formed from non-conducting ma terial.

When the floating piston valves reach their extreme forward positions, the stems of the metallic bodies thereof will contact with the conductor rods 88 and Ill. The device is grounded to the chassis of the vehicle in any desired way. The master cylinder I is rigidly secured to the frame of the vehicle in the ordinary manner, and, as shown, a bolt 16 is employed for that purpose, which extends through the flange on the master cylinder, and a part of the vehicle frame.

Again referring to Figure 'l of the drawings, it will be noted that we provide a pair of signalling lamps TI and I8, which can be arranged at a convvenient point on the vehicle, such as the instrument board. The lamp 11 can be provided for the front brakes'and the lamp I8 can be provided for the rear brakes. Electrically connected with one contact of the lamp I1 is the conductor 13, and extending from the other contact of the lamp TI is a conductor wire I8. Electrically connected with one contact of the lamp I8 is the conductor 14-, and leading from the other contact of lamp I8 is a conductor 88. The conductor wires 18 and 88 can be connected together and electrically cona storage battery 82. The other terminal can be grounded, as at 88, to the frame of the vehicle. A manually operated switch 8! can be interposed in-the length of the conductor 8| for rendering the lamps I1 and II inoperative, when desired.

In operation of 6hr improved safety device, the

valve ii is normally positioned as shown in Figure of the drawings. Hence; the divergin nassageways 51 and 58 of the valve are out of alignment with the diverging passageways-l8 and ll formed in the block 12, but the passageway 58- aligns or registers with the longitudinal pasageway 38. Thus, when the operator applies the brakes, and the rod 28 is pressed forwardly, the fluidwillbeforcedthrmlghthepassagewayflby the piston l8, and the fluid will flow through the tapered bore 4!, through the axial passageway I, through the'passageways- 58, 36, and II, fln-ough the ports 38 and .38, into the cylinders 88 and Il in rear of the floating piston valves.

These valves will be-forced forwardly, and the fluid in front of the same will-be forced out of the bosses 8i and tothebrahingcylindersofthe wheels. Should a leak occur in the line, the fluid pressureinrearofthefloatingpistonvalveswill move the valves to the extreme front of the cylinders, and the bodies of the valves will engage the conductor 8|, through switch 84, through wires I8 and 88, through the lamps l1 and 18, through the piston valves tothe block, thence to the ground, and back to the battery. The lamps will then be in operation and indicate to the driver that the brakes need attention. Obviously, the piston valves can operate independently of one another, so that should a leak occur, say in a front brake, only one piston valve will be moved forwardly to its extreme position for closing the circuit through its indicating lamp. The other piston valve will be operative, and hence permit operation of its brake.

After a leak has occurred, and the same has been repaired, it is necessary to recharge the sys passageway 35, through the valve 5|, and through the diverging'passageways 51, 58, 43, and 44, into the forward ends of the cylinders 38 and 34, in advance of the floating pistons, and the pistons will be returned to their normal positions.

As the floating pistons return to their normal positions, the fluid in rear of the same, will back up in the passageway 36, and this fluid is permitted to escape by means of the bleed passageway I, which will be inalignment with the iongitudinal extending passageway 36 formed in theblock. Obviously, this loss of fluid willbe slight and the passageway can be recharged from the reservoir. As shown,'the reservoir -has communication with the master cyiinder through ports 85 and 88. The port 86 is located in advance of the normal rearmost position of'the main operating piston it, while the port 85 islocated intermediate the piston so as to form means for lubricating the same during the reciprocation .thercof.

We prefer to provide means for indicating the height of the fluid in the reservoir, and hence a sight glass 8i can be provided. This sight glass canbesetpartiallyinagroove 81 formedin the front wall of the reservoir, and the lower end of the tube communicates with a passageway 88 and 88 formed in the block 32. This sight tube 86' can extend into a lip 88 formed on the cover l2, and can be secured in placeby means of a vented PM I threaded into the. lip.

'ii'he reservoir can be-recharged by removing the screw 8|, or by removing a plug M'carrled by the central portion ofthe: cover. If preferred, the plug 92 can be-entirely eliminated.

In the smnmers'eason it is highly important that means be provided ro r care of the exconnect the passageway 88 with the cylinders 83 "and 84, slightly inadvanoe of the normal position of the piston valves l5 and It. By this arrangement, when the fluid'expandsin the cylinders, 15

the same can flow to the ports 92 and 93 into the passageway 99, and thence into the reservoir. Obviously, when the pistons move forwardly, the ports 92 and 93 are cut off. To prevent flow of fluid into the cylinders in front of the piston valves in the reservoirs, ball valves 94 and 95 are provided, and these valves normally close the ports 92 and 93. These valves are readily unseated when the oil expands in the cylinders. Screws 96 and 91 are provided for holding the ball valves on their seats during the recharging of the cylinders.

Means is also provided for operating a stop tail light signal lamp 90, by fluid pressure, upon the application of the brakes. By referring to Figures 5 and '7 of the drawings, it will be noted that this means can consist of a laterally extending cylinder 99 formed on the forward end of the master cylinder I0. A port I00 connects the laterally extending cylinder 99 with the master cylinder, and when the operating piston I9 moves forwardly, a certain quantity of the fluid under pressure will be forced into the lateral cylinder 99, through said port I00.

Slidably mounted within the lateral cylinder 99 is a piston IOI, which is adapted to engage a contact post I02, when the piston IN is moved forwardly. An expansion coil spring I03 is employed for normally holding the piston away from the contact. Secured to the post I02 by suitable nuts-is a conductor wire I04, which is extended to one terminal of the stop signal light 98. The other terminal of the stop signal light is grounded, as at I05, to the frame.

Electrically connected with the piston IN 'is a feed wire I06, which is connected to the wire 8| between the battery 92 and the control switch 84. Thus, the flow of current is as follows:

Through the post I02, through the wire I04, through lamp 98, wire I05, through the frame of the vehicle, through the battery, through wire I06, back to the piston.

By referring to Figures 1 to 5 inclusive, it will be noted that the block 32 is bored out to form the various passageways, and the outer ends of the bores are closed by suitable threaded stop plugs I01, or the like.

As heretofore intimated, the block 32 can be formed separate from the master cylinder, so that our improved safety device can be incorporated with braking systems now installed on vehicles in use.

Reference can now be had to Figures 8 and 9, and it will be noted that we provide a pair of connected cylinders H0 and III. Disposed between the cylinders and adjacent to one end thereof is a nipple H2, which is adapted to be threaded into one end of the usual master cylinder H9 of the braking cylinder. This nipple is provided with a bore I which communicates with the axial bore of a single control valve H5. This valve functions identically with the valve 5i, and the entire device is constructed the same as the safety device previously described, the only difference being that communication is had with the master cylinder through the nipple H2 instead of the transverse bore 95, shown in Figure 4.

From the foregoing description it can be seen that we have provided an exceptionally simple and durable safety device for the hydraulic braking system of motor vehicles in which a single valve is employed for controlling the flow of fluid to the safety cylinders.

Changes in details may be made without departing from the spirit or the scope of outinvention, but what we claim as new is:

1.-In a fluid brake system for motor vehicles, a master cylinder, a safety device including a block having a pair of spaced parallel cylinders therein, a passageway in said block between the cylinders having communication with the master cylinder, a valve having an axial bore communicating at all times with the passageway, and means controlled by said valve for directing the flow of fluid simultaneously to one end of the parallel cylinders when in one position, and for simultaneously controlling the flow of fluid to the other end of the parallel cylinders when in another position.

2. In a fluid brake system for motor vehicles, a master cylinder, a safety device including a block having a pair of spaced parallel cylinders therein, a passageway in said block between the cylinders having communication with the master cylinder, a valve having an axial bore communicating at all times with the passageway, means controlled by said valve for directing the flow of fluid simultaneously to one end of the parallel cylinders when in one position, and for simultaneously controlling the fiow of fluid to the other end of the parallel cylinders when in another position, and means for establishing a bleed with the parallel cylinders when the valve is in one of its positions.

3. In a fluid brake system for motor vehicles, a master cylinder, a safety device including a block having a pair of spaced parallel cylinders therein and a bore between said cylinders, a rotatable valve having an axial bore in communication with the first mentioned bore at all times, said firstmentioned bore being in communication with the master cylinder passageways on one side of the first mentioned bore communicating with the parallel cylinders at one end, a passageway on the other side of the first mentioned bore communicating with the opposite ends of the parallel cylinders, floating piston valves in said parallel cylinders, means for connecting one end of one of the parallel cylinders with the front brakes of the cylinders, means for connecting one end of the other of said parallel cylinders with the rear brakes of the vehicle, said rotatable valve having ports for connection with the first mentioned passageway, when the valve is in one position for connecting said passageway with its bore and said valve having another. port therein for connection with the other passageway of the block when the valve is in another position for connecting said last mentioned passageway with the bore of the valve.

4. In a fluid brake system for motor vehicles, a master cylinder, a safety device including a block having a pair of spaced parallel cylinders therein and a bore between said cylinders, a rotate able valve having an axial bore in communication with the first mentioned bore at all times, said first mentioned bore being in communication with the master cylinder passageways on one side of the first mentioned bore communicating with the parallel cylinders at one end, a passage way on the other side of the first mentioned bore communicating with the opposite ends of the par allel cylinders, floating piston valves in said parallel cylinders, means for connecting one end of one of the parallel cylinders with the front brakes of the cylinders, means for connecting one end of the other of said parallel cylinders with the rear brakes of the vehicle, said rotatable valve having ports for connection with the first mentioned passageway, when the valve is in one position-for 25 with the passageway,

connecting said passageway with its bore and said valve having "another port therein for connection with the other passageway of the block when the valve is in another-position for connecting said last mentioned passageway with the bore of the valve, said valve having a bleeding passageway therein for connection with a certain passageway in the block when the valve is in one position.

5. In a fluid brake system for motor vehicles, a master cylinder, a reservoir carried by the cylinder and having communication therewith, a safety device including a block having a pair of spaced parallel cylinders therein, means for establishing communication between the master cylinder and the opposite ends of the parallel cylinders, floating piston valves in the parallel cylinders, one of the parallel cylinders having connection with the front brakes of the vehicle, and the other of said parallel cylinders having connection with the rear brakes of the vehicle, and means for taking careof expansion of fluid in advance of the floating pistons including a passageway in the block having communication with the reservoir, ports in the block communicating and with the cylinders slightly in advance of the normal position of the floating pistons, one-way opening valves for controlling the flow of fluid to the ports.

6. In a fluid brake system for motor vehicles,-

a master cylinder, a reservoir carried by the cylinder and having communication therewith, a

safety device including a block having a pair of spaced parallel cylinders therein, means for establishing communication between the master cylinder and the opposite endsof the parallel cylinders, floating piston valves inrthe parallel cylinders, one oifthe parallel cylinders having connection with the front-brakes of the vehicle,

and the other of said parallel cylinders having connection with the rear brakes oi the vehicle, and means for vtakingcare of expansion of fluid in advance of the floating pistons includinga passageway in the block havingvcommunication with the reservoir, ports in the block communicating with thepassageway, and with the cylinders slightly in advance of the normal position of the floating pistons, one-wayyopening valves for controlling the flowof fluid to the ports, and manually operated means for holding the valves on their seats against movement when: so desired. EDWARD C. HESS.

EMIL HESS. 

